Lubricants containing alkylene oxide reaction products



United States Patent f 3,272,744 LUBRICANTS CONTAKNKNG ALKYLENE OXIDE REACTIUN PRODUCTS Elmer E. Schallenherg, Fishldll, and Roger G. Lacoste,

Hopewell Junction, N.Y., and Herman I). Kluge, deceased, late of liishkill, N.Y., by Hazel E. Kluge, administratrix, Fishkill, N.Y., assignors to Texaco Inc, New York, N.Y., a corporation of Delaware No Drawing. Filed Oct. 27, 1964, Ser. No. 407,285 15 Claims. (Cl. 252--32.7)

This application is a continuation-in-part of now abandoned Serial No. 59,507 filed September 30, 1960.

This invention rel-ates to lubricant compositions containing novel ashless detergents. More particularly, it relates to lubricants containing mono-hydroxyalkyl hydrocarbyl thiophosphonates.

U.S. 3,087,956 discloses novel mono-hydroxyalkyl hywherein R is a hydrocarbyl radical, R and R are hydrogen or a monovalent aliphatic hydrocarbyl radical containing 1-6 carbon atoms and X is sulfur or a mixture of a major portion of sulfur and a minor portion of oxygen. The mono-hydroxyalkyl thiophosphonates are present in the lubricating oil in a concentration sufiicient to impart detergent and dispersant properties thereto. In finished lubricants, the mono-hydroxytalkyl thiophosphonat-e is usually present in a concentration between 0.2 and 10.0 weight percent.

The mono-hydroxyalkyl hydrocarbyl thiophosphonates employed as ashless detergent additives in the lubricant compositions of this invention are prepared by reacting an alkylene oxide with a hydrocarbyl thiophosphonic acid obtained from a hydrocarbon- P 8 reaction product by hydrolysis with steam and subsequent treatment of the hydrolyzed product to remove inorganic phosphorus acids. The action of alkylene oxide with hydrocarbyl thiophosphonic acid is effected at temperature between about 60 and 150 C. and heating under reflux for a period of time ranging from 0.5-2.0 hours. The reaction mixture is then blown with an inert gas such as nitrogen at a temperature between about 100 and 125 C. until the product is dry and free of unreacted alkylene oxide. A monohydroxyalkyl hydrocarbyl thiophosphonate of the structure shown above is obtained on cooling the reaction product. Mono-hydroxyalkyl hydrocarbyl thiophosphonates are also prepared by reacting alkylene carbonates such as ethylene carbonate and propylene carbonate with hydrocarbyl thiophosphonic acids obtained as outlined above. The reaction of alkylene carbonate with hydrocarbyl thiophosphonic acid is usually effected in the presence of an alkaline catalyst such as potassium carbonate.

Hydrocarbyl thiophosphonic acids employed in prepar- 3,272,744. Patented Sept. 13, 1966 ing the mono-hydroxyalkyl thiophosphonate employed as a lubricant additive have the general formula:

if RPOH wherein R is a hydrocarbyl radical which may be aromatic, aliphatic or cycloaliphatic in nature and which usually contains 12 or more carbon atoms and X is sulfur or a mixture of a major portion of sulfur and a minor portion of oxygen. The R radical in this formula is advantageously a polyolefin radical such as polyisobutylene or polypropylene having an average molecular weight between about 250 .and 50,000 since such materials are the preferred materials for reaction with P 5 The preferred hydrocarbyl radical is a polybutene radical having a molecular weight between 600 and 5000.

The hydrocarbyl thiophosphonic acids of the above formula are prepared by reaction of P 5 with a hydrocarbon, the reaction mixture constituting between about 5 and 40 wt. percent P 8 at an elevated temperature of between about and 320 C. in a non-oxidizing atmosphere, for example, under a blanket of nitrogen followed by hydrolysis of the resulting product by contact with steam at a temperature between about 100 and 260 C. Steam treatment of the P S -hydrocarbon reaction product results in its hydrolysis to form inorganic phosphorus acids and a hydrocarbyl thiophosphonic acid of the structure shown above.

The inorganic phosphorus acids are removed from the hydrolyzed reaction product prior to reaction wit-h alkylene oxide or alkylene carbonate to form the novel monohydroxyalkyl hydrocarbyl thiophosphonates. Removal of the inorganic phosphorus acids from the hydrolyzed product can be effected by the procedures disclosed in U.S. 2,951,835 and 2,987,512 wherein removal is effected by contact with synthetic hydrous alkaline earth metal silicates and synthetic hydrous alkali metal silicates, respectively. Inorganic phosphorus acids can also be removed by extraction with anhydrous methanol as disclosed in U.S. 3,135,729.

Alkylene oxides which react with hydrocarbyl thiophosphonic acids on about an equimolar basis in the absence of catalyst to form the rnono-hydroxyalkyl thiophosphon'ate additives of this invention are represented by the formula:

0 M ena H II wherein R and R" are hydrogen or an aliphatic hydrocarbyl radical containing l-6 carbon atoms. Examples of effective olefin oxides are the following: Ethylene oxide, propylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, 1,2-pentylene oxide, 2,3-pentylene oxide, 1,2-hexylene oxide, 3-methyl-1,2-pentylene oxide, 2,3-octylene oxide, 4-methyl-2,3-octylene oxide, 4-methyl-l,2-hexylene oxide, and 3-methyl-l,2-butylene oxide.

Reaction of alkylene oxide with hydrocarbyl thiophosphonic acid to produce the mono-hydroxyalkyl hydrocarbyl thiophosphonates is effected :at a temperature between about 60 and 150 C. with temperatures of 80 to C. being preferred. Atmospheric and superatmospheric pressures are employed for the reaction pressure, between about 10 and 500 lbs. p.s.i.g. being advantageous with the lower alkylene oxides.

The mono-hydroxyalkyl hydrocarbyl thiophosphonates are generally prepared by adding an excess of alkylene oxide to the hydrocarbyl thiophosphonic acid prepared by hydrolysis of a hydrocarbon-P 8 reaction product. The mol ratio of alkylene oxide to acid in the reaction mixture varies between 1 and 4 but usually falls between 1.1 and 1.5. Excess \alkylene oxide is removed after completion of reaction by blowing the reaction mixture at elevated temperatures, generally with an inert gas such as nitrogen.

Mono-hydroxyalkyl hydrocarbyl thiophosphonates effective as lubricating oil detergents are illustrated by the following:

mono(2-hydroxyethyl) polybutene (780 M.W.)

thiophosphonate,

mono(2-hydroxyethyl) polybutene (940 M. W.)

thiophosphonate,

mono(2-hydroxyethyl) polybutene (1100 M.W.)

thiophosphonate,

mono-hydroxypropyl polybutene (940 M.W.)

thiophosphonate,

mono-hydroxybutyl polybutene (1200 M.W.)

thiophosphonate,

mono-hydroxyamyl propylene-butylene copolymer (1100 M.W.) thiosphosphonate,

mono-hydroxyhexyl polybutene (940 M.W.)

thiophosphonate,

mono-hydroxyoctyl polybutene (780 M.W.)

thiophosphonate,

mono-hydroxyethyl polybutene (940 M.W.)

thiophosphonate,

mono-hydroxypropyl polybutene (1500 M.W.)

thiophosphonate and mono(2-hydroxyethyl) polybutene (1500 M.W.)

thiophosphonate.

The hydrocarbon mineral oils usable in this invention can be paraffin base, naphthene base or mixed paraffinnaphthene base distillate or residual oils. Parafiin base distillate lubricating oil fractions are used in the formulation of premium grade motor oils such as are contemplated in this invention. The lubricating base generally has been subjected to solvent refining to improve its lubricity and viscosity temperature relationship as well as solvent dewaxing to remove waxy components and improve the pour of the oil. Broadly speaking, mineral lubricating oils having an SUS viscosity at 100 F. between 50 and 1000 may be used in the formulation of the improved lubricants of this invention but usually the viscosity range falls between 70 and 300 at 100 F.

The mineral lubricating oils containing rnono-hydroxyalkyl esters of hydrocarbyl thiophosphonic acids usually contain other additives designed to impart other desirable properties thereto. For example, VI improvers such as the polymethacrylates are normally included therein as are corrosion inhibitors and other dispersants.

A widely used VI improver is :a polymethacrylate of the general formula:

wherein R is an aliphatic radical.

The most commonly used supplementary detergent is an alkaline earth metal 'alkyl phenolate; barium nonyl phenolate, barium dodecyl cresolate and calcium dodecyl phenolate are examples of such detergents. These products which are well known detergent additives are usually present in the lubricating oil in a concentration between 0.1 and 5.0 weight percent.

The most commonly used inhibitor and antioxidant is a divalent metal alkyl dithiophosphate resulting from the neutralization of a P S -alcohol reaction product with a divalent metal or divalent metal oxide. Barium and zinc alkyl dithiophosphates are the most widely used oxidation and corrosion inhibitors. Metal dialkyl dithiophosphates are usually present in the lubricant in a concentration between 0.1 and 3.0 weight percent.

Synthetic lubricating bases of the ester or ether type may also be used as the lubricating oil. High molecular weight, high boiling liquid aliphatic dicarboxylic acid esters possess excellent viscosity-temperature relationships and lubricating properties and are finding ever-increasing utilization in lubricating oils adapted for high and low temperature lubrication; esters of this type are used in the formulation of jet engine oils. Examples of this class of synthetic lubricating bases are the diesters of acids such as sebacic, adipic, azelaic, alkenyl succinic, etc.; specific examples of these diesters are di-Z-ethylhexyl sebacate, di- Z-ethylhexyl azelate, di-Z-ethylhexyl adipate, di-n-amyl sebacate, di-2-ethylhexyl n-dodecyl succinate, di-2-ethoxyethyl sebacate, di-2-methoxy-2-ethoxyethyl sebacate (the methyl Carbitol diester), di-2-ethyl-2-n-butoxyethyl sebacate (the 2-ethylbutyl Cellosolve diester), di-Z-n-butoxyethyl azelate (the n-butyl Cellosolve diester) and di-2'-nbutoxy-2-ethoxyethyl-n-octyl succinate (the n-butyl Carbitol diester).

Polyester lubricants formed by a reaction of an aliphatic dicar-boxylic acid of the type previously described, a dihydroxy compound and a monofunctional aliphatic monohydroxy alcohol or an aliphatic monocarboxylic acid in specified mol ratios are also employed as the synthetic lubricating base in the compositions of this invention; polyesters of this type are described in US. 2,628,974. Polyesters formed by reaction of a mixture containing specified amounts of heptanediol, sebacic acid and 2-ethylhexanol and of a mixture containing adipic acid, diethylene glycol and 2ethylhexanoic acid illustrate this class of synthetic polyester lubricating bases.

Polyalkylene ethers as illustrated by polyglycols are also used as the lubricating base in the compositions of this invention. Polyethylene glycol, polypropylene glycol, polybutylene glycols and mixed polyethylene-polypropylene glycols are examples of this class of synthetic lubricating bases.

The sulfur analogs of the above-described diesters, polyesters and polyalkylene ethers are also used in the formulation of the lubricating compositions of this invention. Dithioesters are exemplified by di-Z-ethylhexyl thiosebacate and di-n-octyl thioadipate; polyethylene thioglycol is an example of the sulfur analogs of the polyalkylene glycols; sulfur analogs of polyesters are exemplified by the reaction product of adipic acid, thioglycol and Z-ethylhexyl mercaptan.

The mono-hydroxyalkyl hydrocarbyl thiophosphonates are present in lubricating oils in concentrations suflicient to impart dispersant properties thereto. In concentrates used in the formulation of finished lubricants, the concentration of the mono-hydroxyalkyl hydrocarbyl thiophosphonate can be as high as 50%. In finished lubricants, the concentration of the additive falls between 0.2 and 10.0 weight percent with concentrations between 1.0 and 5.0 weight percent normally being employed.

The following examples further illustrate the invention but one not to be construed as limitations thereof.

Example 1.A polybutene-P 5 reaction product was prepared by reacting polybutene having an average molecular weight of about 940 with P 8 in a mol ratio of polybutene to P 5 of 1.1 and in the presence of sulfur in an amount equal to 1.3 weight percent of polybutene. After reaction at 450 F., until the mixture is soluble in n-pentame, the reaction product was diluted with approximately 140 weight percent of a naphthene base oil having an SUS viscosity at F. of 100, steamed at 350 F. for 10 hours in a nitrogen atmosphere, and then dried by passage of nitrogen therethrough at 350 F. The hydrolyzed product was extracted with 50% by volume of methyl alcohol at F. to give a methanol extract containing inorganic phosphorus acids and a lubricating oil raffinate containing olefin-P 5 product which after stripping free of methanol had a Neut. No. of 23.1.

Example 2.-Approximately 15 gallons of a polybutene (average molecular weight 940) thiophosphonic acid simi lar to that prepared in Example 1 was reacted in 6000 g. batches with ethylene oxide in a 12-liter, 3-necked flask equipped with a stirrer, gas inlet tube and a thermometer. Air was removed from the system by heating to 93 C. while blowing with nitrogen. After addition of a Dewar reflux condenser containing a Dry Ice-acetone mixture to the system, ethylene oxide was added at a rate sufficient to maintain a gentle reflux from the condenser. The nitrogen flow was reduced to a trickle during the ethylene oxide addition. When rapid reflux of ethylene oxide was noted, ethylene oxide addition was stopped and the reaction mixture allowed to reflux for approximately 2 hours to assure completion of reaction. Excess ethylene oxide was then removed from the reaction mixture by increasing the nitrogen rate and blowing for 2 hours at a temperature of approximately 93 C. After 2 hours of nitrogen blowing, the product was cooled to room temperature. This procedure was repeated until 15 gallons of mono-hydroethyl polybutene thiophosphonate was obtained for subsequent engine testing. Analysis of a composite sample gave the following results:

Calculated Found Neut. N 0.0 0. 69 Hydroxyl No 17 21 Percent Phosphorus.... 0. 9G 0. 93 Percent Sulfur 0.99 0. 62

Example 3.-An SAE 10W30 motor oil containing a monohydroxyethyl hydrocarbon thiophosphonate as a detergent'dispersant was formulated as follows:

TABLE I Concentration, wt. percent Refined paraffinic distillate oil 88.92

Mono(2-hydroxyethyl) polybutene (av. molecular Inspection tests on this SAE l0W-30 motor oil were obtained with the following results:

Gravity, API 29.5 Flash, COC F. 445 Viscosity, SSU at 0 F. (extrap) 12,000

Viscosity, SSU at 100 F. 330 Viscosity, SSU at 210 F. 62 Viscosity index 133 Pour, F. -35 Neut. No. (oxalate), alk. 0.63 Ash, sulfated, percent wt. 0.82 Barium, percent Wt. 0.29 Zinc, percent wt. 0.10

The mono(2-hydroxyethyl) polybutene thiophosphonate employed in the formulation of the above 10W-30 lubricant was of the type prepared in Example 2 and was obtained by reaction of ethylene oxide with polybutene thiophosphonic acid obtained by reacting polybutene of 940 average molecular weight with P 8 steaming the reaction product and removing inorganic phosphorus acids from the steamed product by methanol extraction.

The mono(2-hydroxyethyl) polybutene thiophosphonate has the formula:

wherein R is a polybutene radical of 940 average molecular weight and X is a mixture of a major portion of sulfur and a minor portion of oxygen.

This SAE lOW-30 oil was evaluated in both the Chevrolet SII Test and in the extended version of the Chevrolet-L-4 Test, which has a CRC designation of L4- 1252.

The Chevrolet SII Test is conducted under conditions simulating low temperature operation wherein deposit formation is most pronounced. The merit system of evaluation involves visual examination of the engine parts after disassembly and their rating according to deposits by comparison with standards which have assigned ratings. Individual parts, e.g. pistons, are rated in the Chevrolet SII Test on the system wherein a 10 rating designates a clean part, that is, without deposits, and a rating of 0 represents the worst condition. Total engine varnish and total engine sludge are rated on a system wherein 50 designates the absence of deposits and 0 indicates the worst condition.

The Chevrolet L-4 Test is used to evaluate the performance of a motor oil under high temperature conditions where wear and corrosion are problems. In the extended Chevrolet L-4 Test, which in this instance was of 108 hours duration, the individual pistons are also rated by a merit system wherein 10 denotes a clean piston, with 0 designating the worst condition; the total engine deposits are evaluated on a system wherein designates a perfectly clean engine and 0 the worst condition.

In the following table there are shown Chevrolet SII and Chevrolet L-4 Tests results with the above SAE 10W-3O motor oil, Lubricant A, containing a mono-hydroxyethyl polybutene thiophosphonate as a dispersant in comparison with a 10W-30 motor oil, Lubricant B, which has a balanced additive formulation comprising barium petroleum sulfonate, sulfurized barium alkylphenolate and Zinc dialkyl dithiophosphate. The comparison oil which meets MIL-L-2l04A (Supplement I) specifications containing 0.75 wt. percent barium and 0.088% zinc in contrast with the 0.29 wt. percent barium and 0.1 wt. percent zinc contents of the 10W-30 oil containing mono-hydroxyethyl polybutene thiophosphonate as a dispersant.

TABLE II.-ENGINE TESTS ON SAE 10W-30 The above data indicate that 10W-30 formulations containing mono-hydroxyethyl polybutene thiophosphonate as a dispersant gave excellent performance under conditions simulating both low temperature and high temperature operation.

An SAE 10W-30 formulation containing mono-hydroxyethyl polybutene thiophosphonate as a dispersant was also evaluated in the so-cal-led Caterpillar L-l Test, was has a CRC designation of L-1.545. This test consisted of running a single-cylinder Caterpillar diesel test engine having an oil spray cooled aluminum alloy piston with three compression rings and one oil ring operating in a hardened cylinder liner on 25 gallons of the oil to be tested as the crankcase lubricant. The test was run on a dirty diesel fuel containing 1% sulfur. In this test, the grooves, lands and under pistons were clean indicating that this oil qualified under the rigid cleanliness requirement of MIL-L-2l04A (Supplement I) specifications.

The excellent wear characteristics of the SAE W-3O formulation containing mono-hydroxyethyl polybutene thiophosphonate were demonstrated in the CPR engine Low Temperature Ring Wear Test which measures the amount of protection afforded by an oil against corrosion wear resulting during low temperature engine operation. This test is performed in a CFR single engine 3% x 4 internal combustion engine having a cast iron piston and babbitt metal bearings operating at 900 r.p.m. Oil pressure was about p.s.i. and oil temperature in the sump was about 120 F. with the temperature of cooling water at the discharge of 80 F. In this test, the mono-hydroxyethyl polybutene thiophosphonatecontaining 10W-30 motor oil gave a top compression ring weight loss of only 0.081 gm.

An airplane engine oil was formulated using monohydroxyethyl polybutene thiophosphonate as an ashless dispersant additive. The base oil consisted of a parafiin base residum which has been propane deasphalted, furfural refined, solvent dewaxed and clay filtered; the base oil had a VI of 96.6 and an SUS at 210 F. of about 120. An antioxidant was also added to the mono-hydroxyalkyl polybutene thiophosphonate containing oil; the specific anti-oxidant added was 4,4'-methylene-bis-2,6-di-t-butylphenol. This formulation was compared in the Continental Aircraft Engine Test with the base oil and with a commercial additive-containing airplane engine oil containing a mixture of magnesium and zinc alkylphenolates.

The Continental Engine Test is carried out on a 4- cylinder Continental A-80 engine employing as a fuel an aviation gasoline grade AV80+3 cc. TEL/ gal. The following engine opearting conditions are maintained during the test run:

Top Ring Travel Temperature Speed, r.p.m., 2,400 Cylinder 1 410 F. Load, B.H.P., 56-59 Cylinder 2 390 F Oil Temperature (Gallery) F., 220 Cylinder 3 420 F Air/fuel ratio, 12.5:1 Cylinder 4 350" F Duration 140 hours.

The demerit rating system is employed to evaluate the performance of the lubricant; an engine part which is clear or otherwise in excellent condition is assigned a numerical value of 0 demerits, whereas a rating of 10 demerits represents the worst condition for the particular part. Total demerits is the sum of the individual demerit rating of the engine parts being inspected.

The data in the foregoing table shows the airplane engine oil containing the ashless additive combination of mono-hydroxyalkyl hydrocarbyl thiophosphonate and antioxidant is significantly superior to the base oil which is widely used by the commercial airlines. In the Continental Engine Test, the mono-hydroxyethyl polybutene thiophosphonate-containing oil gave approximately equivalent results to the oil containing magnesium and zinc alkylphenolates but has a decided advantage thereover in that it is an ashless formulation which is a requirement of a large number of commercial airlines.

The effectiveness of mono-hydroxyethyl polybutene thiophosphonate as a detergent was also demonstrated in the Airplane Oil Detergency Test which is run in the CFR High Speed Engine. This test is evaluated on a Total Demerit basis using the rating system employed in the Continental Engine Test. The base oil employed in this test was the same as employed in the Continental Engine Test described above.

TABLE IV Airplane oil detergency test: Total demerits Base oil 285 Base oil+3 wt. percent of a mixture of magnesium and zinc alkylphenolates 227 Base oil+3.58 wt. percent mono-hydroxyethylpolybutene (940 M.W.) thiophosphonate 143 In the Airplane Oil Detergency Test the monohydroxyalkyl hydrocarbyl thiophosphonate-containing lubricant gave a significantly cleaner engine than either base oil or the commercial oil containing the magnesium-zinc alkylphenolate detergent mixture.

An SAE lOW-30 motor oil was formulated with a monohydroxybutyl polybutene thiophosphonate as a detergent-dispersant. The mono-hydroxybutyl polybutene thiophosphonate was obtained by reacting 1,2-butylene oxide with polybutene thiophosphonic acid obtained by reacting polybutene of 1500 average molecular weight with P 3 hydrolyzing the reaction product by steaming and removing inorganic phosphorous acids from the steamed product by methanol extraction. The monohydroxybutyl polybutene thiophosphonate thus obtained has the formula:

wherein R is a polybutene radical of 1500 average molecular weight and X is a mixture of a major amount of sulfur and a minor amount of oxygen.

The SAE 10W-30 motor oil formulated with monohydroxybutyl polybutene thiophosphonate as a detergent-dispersant had the following composition:

TABLE V Composition, wt. percent Refined paraffinic distillate oil 89.74

Mono(2-hydroxybutyl) polybutene thiophosphonate 3.89 Barium C alkylphenolate 1.76 Zinc isopropyl methyl isobutyl carbinyl di-thiophosphate 0.61 Mineral oil concentrate containing 25% of a copolymer of mixed methacrylate, alkyl esters in which the alkyl groups range from butyl to stearyl 4.00 Dimethyl silicone anti-foam concentrate, p.p.m.

The above SAE 1OW-30 motor oil which contained 0.3 weight percent barium and 0.07 weight percent zinc was evaluated in the Chevrolet S-II Test with the following results:

TABLE VI.Chevrolet S-II Test on SAE l0W-30 Motor Oil Containing Mono-hydroxy Butyl Polybutene Thiophosphonate Ratings Piston varnish 6.5

Total engine varnish 44.3

Total engine sludge 48 Total rating 88.5

The data in the above table indicate that a 10W-30 formulation containing mono-hydroxybutyl polybutene thiophosphonate as a dispersant performs very well in the Chevrolet S-II Test.

Mono-hydroxypropyl polybutene thiophosphonates prepared by reaction of propylene oxide with polybutene thiophosphonic acid obtained by reaction of P 8 with a polybutene having an average molecular weight between 250 and 50,000, hydrolysis of the P S -polybutene reaction product with steam and removal of inorganic phosphorus acids by methanol extraction are also effective detergentdispersants for lubricating oils.

In general, the preferred detergent-dispersant hydroxyalkyl hydrocarbyl thiophosphonates of this invention result from the reaction of ethylene, propylene and butylene oxides with polybutene thiophosphonic acids in which the polybutene has an average molecular weight between 250 and 50,000 and preferably between 600 and 5000. The resulting products are the 2-hydroxyethyl-, the 2-hydroxypropyland the 2-hydroxybutyl mon-oesters of polybutene thiophosphonic acid We claim:

1. A lubricating composition comprising a lubricating oil as a major component and an additive selected from the group consisting of mono-hydroxyalkyl hydrocarbyl thiophosphonate and mixtures of said thiophosphonate and corresponding monohydroxyalkyl hydrocarbyl phosphonate, said additive being present in an amount sufficient to impart detergent properties thereto, said thiophosphonate having the following formula:

where-in R is a monovalent hydrocarbyl radical containing at least 12 carbon atoms, R and R" are selected from the group consisting of hydrogen and monovalent aliphatic hydrocarbyl radicals containing 1-6 carbon atoms and X is sulfur, said mixture consisting of a major amount of said thiophosphonate and a minor amount of said corresponding phosphonate where X is oxygen.

2. A lubricating composition according to claim 1 in which said R is a polybutene radical having .a molecular weight between about 250 and 50,000.

3. A lubricating composition according to claim 1 in which said additive is present in a concentration between 0.2 and 10.0 weight percent.

4. A lubricating composition according to claim 1 in which said lubricating oil is a mineral lubricating oil having an SUS viscosity at 100 F. between 50 and 1000.

5. A lubricating composition according to claim 1 in which said thiophosphonate is a mono-hydroxyethyl hydrocarbyl thiophosphonate having the formula:

in which R is a polybutene radical having a molecular weight between about 250 and 50,000 and said additive is said mixture.

6. A lubricating composition according to claim 1 in which said thiophosphonate is a mono(Z-hydroxyethyl) polybutene thiophosphonate in which said polybutene has an average molecular weight of 940.

7. A lubricating composition according to claim 1 in which said thiophosphonate is a mono-hydroxypropyl polybutene thiophosphonate having the general formula:

in which R is a polybutene radical having an average molecular weight between about 250 and 50,000 and said additive is said mixture.

8. A lubricating composition according toclaim 1' in which said thiophosphonate is a mono(Z-hydroxypropyl) polybutene thiophosphonate in which said polybutene has an average molecular weight of 940.

9. A lubricating composition according to claim 1 in which said thiophosphonate is a mono-hydroxybutyl polybutene thiophosphonate of the general formula:

in which R is a polybutene radical having an average molecular weight between about 250 and 50,000 and said additive is said mixture.

10. A lubricating composition according to claim 1 in which said thiophosphonate is a mono(Z-hydroxybutyl) polybutene thiophosphonate in which said polybutene has an average molecular weight of 1500.

11. A lubricant composition comprising a mineral lubricating oil as the major component, 0.210.0 weight percent of an additive selected from the group consisting of mono-hydroxyalkyl hydrocarbyl thiophosphonate and a mixture of said thiophosphonate and corresponding monohydroxyalkyl hydrocarbyl phosphonate, said mono-hydroxyalkyl hydrocarbyl thiophosphonate of the general formula:

wherein R is a monovalent hydrocarbyl radical containing at least 12 carbon atoms, R and R" are selected from the group consisting of hydrogen and monovalent aliphatic hydrocarbyl radicals containing 1-6 carbon atoms, and X is sulfur, an alkaline earth metal alkylphenolate in a concentration between 0.1 and 5.0 weight percent, a divalent metal alkyl dithiophosphate in a concentration between 0.1 and 3.0 weight percent, said mixture consisting of a major amount of said thiophosphonate and a minor amount of said corresponding phosphonate where X is oxygen.

12. A lubricant composition according to claim 11 in which said mono-hydroxyalkyl hydrocarbyl thiophosphonate is a mono(2-hydroxyethyl) polybutene thiophosphonate in which said polybutene has an average molecular weight between 600 and 5000.

13. A lubricant composition according to claim 11 in which said thiophosphonate in a mono(2-hydroxypropyl) polybutene thiophosphonate in which said polybutene has an average molecular weight between 600 and 5000.

14. A lubricant composition according to claim 11 in which said thiophosphonate is a mono(Z-hydroxybutyl) polybutene thiophosphonate in which said polybutene has an average molecular weight between 600 and 5000.

1-5. A lubricating composition comprising a lubricating oil as the major component, 0.2-10'.0 weight percent of an additive selected from the group consisting of monohydroxyalkyl hydrocarbyl thiophosphonate and a mixture of said thiophosphonate and the corresponding monohydroxyalkyl hydrocarbyl phosphonate, said mono-hydroxyalkyl hydrocarbyl thiophosphonate having the general formula:

wherein R is a monovalent hydrocarbyl radical containing at least 12 carbon atoms, R and R" are selected from the group consisting of hydrogen and monovalent aliphatic hydrocarbyl radicals containing 1-6 carbon atoms, and X is sulfur, an alkaline earth metal alkyl phenolate in a concentration between 0.1 and 5.0 weight percent, and a divalent metal alkyl dithiophosphate in a concentration between 0.1 and 3.0 weight percent, said mixture consist- 1 1 1 2 ing of a major portion of said thiophosphonate and 2. 2,951,835 9/1960 Kluge et a1 260139 minor portion of said phosphonate where X is oxygen. 2,987,512 6/1961 Wisner et a] 260139 FOREIGN PATENTS References Cited by the Examiner 5 838,928 6/1960 Great Bntaln.

UNITED STATES PATENTS 2,587,340 2/1952 Lewis et a1 252-498 DANIEL WYMAN, Primary Examine/3 2,914,478 11/1959 Neff L, G. XIARHOS, Assistant Examiner. 

